The invention relates to plasma display, driving apparatus of plasma display panel and driving system thereof for, for example, display apparatus of personal computer or workstation, a flat type wall hanging television receiver and a display apparatus for advertising and information. This invention is preferably applicable to AC type plasma display.
In plasma display, one field is divided into several sub-fields, and each pixel (cell) is given forth light by exciting a phosphor by ultraviolet rays that are generated by a electric discharge carried out in the cell. The cell that emits light is practiced by an address electric discharge between two set of electrodes which are provided perpendicular to each other on a front side glass substrate and a back side glass substrate respectively and are capable of driving independently.
A first prior art relating to a plasma display is disclosed, for example, Japanese Patent Application Laid-Open No. 1994/186927. In the prior art, the condition of the electric charge particles in all cells is equalized for surely prohibiting lighting for some cells which are not intended to emit light, and two sets of light emitting discharges, that is, a full writing electric discharge and a full erasing electric discharge in each sub-field are carried out so as to be able to use low voltage for an address electric discharge. Therefore, the contrast is deteriorated because light emitting occurs on full panel when black is displayed.
A second prior art is disclosed, for example, Japanese Patent Application Laid-Open No. 1995/49663. In the prior art, the plurality of the sub-fields having the same brightness gradations are arranged to construct a sub-field block, and several blocks are provided. In sub-field blocks, a preliminary discharge including a full writing electric discharge and a fine line erasing electric discharge is performed in one sub-field, and a writing electric discharge and a erasing electric discharge to a pixel is carried out one time. Therefore, deterioration of a panel is reduced and contrast of a display is improved. The second prior art discloses one of the solution to improve the contrast, but no prior art is shown to improve the contrast in which plural sub-fields having different brightness gradations for constructing one sub-field block.
About 3 .mu.sec to 4 .mu.sec is needed to write one line of plasma panel, and an ordinal television display has 480 lines. A writing period of a screen is 1.44 msec if a writing period of one line is 3 .mu.sec, so that 1.44 msec.times.9.apprxeq.13 msec is needed for one field. The period of one field is 16.7 msec. A sustaining period is 16.7 msec minus a writing period and preliminary discharge period, and this period is not so long enough. Further, if a display has 760 lines per a screen like a high definition display, or if a display has 8 sub-fields for constructing 256 gradations, period for writing is not sufficient.